Art of heating steam boilers and similar apparatus



Patented June 27, 1933 PATENT OFFICE mar KOENEMANN, OF HALENSEE NEAR BERLIN, GERMANY A31 03' HEATING STEAM BOILERS AND SIMILAR APPARATUS Io Drawing. Application filed January 21, 1990, Serial No. 422,498, and in Germany January 4, 1929.

The advantages attainable by transmitting in high-pressure boilers and other boilers subjected to a great stress the heat of the heating gases to the liquid to be evaporated not 5 directly, but by the intermediary of an auxiliary liquid are known. However, the advantages of such indirect heating systems are in some cases partly offset and in other cases even wholly ofiset by the great difiiculties connected with the finding out of an auxiliary liquid actually suited for the purpose in view, as all known auxiliary liquids hitherto used for that purpose are either decomposed at the higher temperatures concerned or become solid at a relatively high temperature and change their volume besides, nearly all those auxiliary liquids ali boiler shell and other apparatus, and indeed,

some of them must be scrupulously avoided on account of their poisonous character or their tendency to cause explosions. The same difliculties are the reason for the uselessness of normal auxiliary liquids for the heating of superheaters, intermediate superheaters and feed-water heaters. Finally, also molten metal salts have proved useless from the reasons stated.

All drawbacks stated in the receding paragraph are completely avoide by using as an auxiliary liquida molten metal salt to which small amounts of ammonia have been adjoined.

Thorough tests have proved the fact that one succeeds in the just mentioned manner in producing a heat carrier which even at high temperatures does not afiect normal boiler material. By suitably selec ing the metal salts for the purpose m viewmetal chlorides are articularl suited-as well as he amount 0 the adjomed ammonia, it is also possible to obtain a molten mass that can be heated sufliciently high without decomposing or forming steam. Moreover, the temperature at which the molten mass solidifies can be considerabl reduced, and it is possible to carry out t e method in such a we that the mass solidifies without any material change of its volume, and even so that it solidifies in an amorphous manner like 50 glass.

ect the material of the (ZnCl (NH,))

and chloride of zinc-diammoniacate (ZnCl (NH,)

is formed in which the chloride of zincmonammoniacate predominates, suitable proportions of this mixture for heating at about 350 C. and atmospheric (pressure being about 35% diammoniacate an 65% monammoniacate. This mixture is advantageous because it has a high coeflicient of heat transfer, a low viscosity and a low critical velocity as compared with compounds heretofore used as indirect neatin liquids, such as fuel oil or glycerin. Furt ermore, a large operating temperature range is available with the mixture in molten state, as the boiling point or decomposition temperature of the molten mixture under atmospheric pressure, depending upon the content of ammonia, is from about 570 F. to 930 F. (300 C. to 500 C.) while it is still usably fluid at temperatures as low as 250 F (3.),

Particular advantages are attained if the auxiliary liquid is used for the heating of intermediate superheaters that must be ar- W ranged at some distance from the furnace, as in the immediate neighbourhood of the engine. Under these circumstances the conditions under which the auxiliary liquid solidifies are of particular importance, as, on the one hand, owing to the distance between the service members concerned, the solidification of the auxiliary liquid can take place particularly easily, and on the other hand, greatest care must be taken that damages resultno ing from, or difliculties caused by, starting parts containing solidified liquid are absolutely prevented. Another point to be paid attention to is the slight viscosity of the new heat carrier whereby the resistance to movement in the supply and the discharge pipes etc. and aloqig the heatin surfaces is reduced, and nally also the favorable behaviour of said heat carrier as regards the transmission of the heat.

When making use of the present invention, the reconstruction of low ressure boilers to high-pressure boilers entai s particularly low costs, as the old boilers can be used again in connection with the auxiliary liquid without any material chan the temperature in the boiler becoming higher, it is true, but the stress to which the boiler is subjected by the internal overpressure being obviated. It is then sufiicient to provide a high-pressure evaporator, or two or more such evaporators, in the neighborhood of the old lowressure boiler or boilers and to transmit t e heat from this or these latter to the high-pressure evaporator or evaporators. There is requisite in most of these cases solely the erection of the cheap high-pressure evaporator or evaporators to be heated by the heat-transmitting auxiliary liquid, and the erection of an auxiliary or series turbine which is also cheap.

As above noted, my invention contemplates such equivalents as will be suggested to the skilled chemist by my present disclosure; and this fact is to be considered in connection with the following claims.

I claim 1. The method of heating steam boilers and similar apparatus by the intermediary of a heat-transmitting auxiliary liquid or liquefied substance, consisting in using as such substance a medium liquid throughout the temperature and pressure ranges of use and consistin of a metal halide other than a fluoride to winch an appropriate amount of ammonia has been adjoinedto form a complex compound with the adjoined ammonia as a neutral part, substantially as set forth.

2. The method of heating steam boilers and similar apparatus by the intermediary of a heat-transmitting auxiliary liquid or liquefied substance consisting in using as such substance molten chloride of zink, to which so much ammonia has been adjoined that a mixture of chloride of zink-monoammoniacate and chloride of zink-diammoniacate arises.

3. The method of transmitting the heat of a furnace to steam to be superheated in an intermediate superheater located at the place of use of the superheated steam, consisting in transmitting the heat by the intermediary of a medium liquid throughoutthe temperature and pressure ranges of such use and consisting of a metal halide other than a fluoride to which an appropriate amount of ammonia has been adjoined to form a complex compound with the adjoined ammonia as a neutral part, substantially as set forth.

4. The method of transmitting the heat of a furnace to steam to be superheated in an intermediate superheater located at the place of use of the super-heated steam, consisting in transmitting the heat by the intermediary of molten chloride of zink, to which such an amount of ammonia has been adjoined that a mixture of chloride of zink-monammoniacate and chloride of zink-diammoniacate arises.

5. An indirect heating system employing as the heat carrying medium a molten mixture of chloride of zinc-monammoniacate and chloride of zinc-diammoniacate.

6. An indirect heating system employing as the heat carrying medium a molten mixture of ammoniacates of zinc chloride.

7. An indirect heating system employing as the heat-carrying medium a molten mixs ture of two adjacent ones of the compounds of the series extending from zinc-chloride through the zinc-chloride ammoniacates.

8. An indirect heating system employing as the heat-carrying medium a molten mixture at two adjacent ones of the compounds of a series extending from a zinc-halide other than a fluoride through the ammoniacates thereof.

9. An indirect heating system employing as the heat-carrying medium a molten mixture of two adjacent ones of the compounds of a series extending from a metal-chloride through the ammoniacates thereof.

10. An indirect heating system employing as the heat-carrying medium a molten mixture of two adjacent ones of the compounds of a se ies extending from a metal-halide other than a fluoride through the ammoniacates thereof.

11. An indirect heating system employing as the heat-carrying medium a molten mixture of ammoniacates of a zinc-halide other than the fluoride.

12. An indirect heating system employing as the heat-carrying medium a molten mixture of ammoniacates of metal-chloride.

13. An indirect heating system employing as the heat-carrying medium a molten mixture of ammoniacates of metal-halides other than fluorides.

14. An indirect heating system em loying a heat-carrying medium consisting o -a mixture of addition compounds of zinc-halides other than fluorides with ammonia as an additive neutrnlly combined constituent.

15. An indirect heating system employing a heat-carrying medium consisting of a mix ture of addition compounds of metal-halides other than fluorides with mnm mia as an additive nentrnlly combined constituent.

16. An indirect heating system en'iploying as the heat-carrying medium a molten mixture essentially consisting of chloride of zincmonammoniacate and chloride of zinc-diammoniacate.

17. An indirect heating system employing as the heat-carrying medium a molten mixture essentially consisting of ammoniacates of zinc-chloride.

18. An indirect heating system employing as the heat-carrying medium a molten mix- ERNST KOENEMKNN.

CERTIFICATE OF CORRECTION.

Patent No. 1,916,172.

June 27, 1933.

ERNST KOENEMANN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

"steam" read "vapor"; and

Page 1, line 43, for

that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 22nd day of August. A. D. 1933.

(Seal) M. J. Moore.

Acting Commissioner of Petente.

ture essentially consisting of chloride of zincmonammoniacate and chloride of zinc-diammoniacate.

17. An indirect heating system employing as the heat-carrying medium a molten mixture essentially consisting of ammoniacates of zinc-chloride.

18. An indirect heating system employing as the heat-carrying medium a molten mix- ERNST KOENEMKNN.

CERTIFICATE OF CORRECTION.

Patent No. 1,916,172.

June 27, 1933.

ERNST KOENEMANN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

"steam" read "vapor"; and

Page 1, line 43, for

that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 22nd day of August. A. D. 1933.

(Seal) M. J. Moore.

Acting Commissioner of Petente. 

